N-port Pi-networks can be extracted directly from Y-parameters. Likewise, two-port T-networks can be extracted directly from two-port Z-parameters. However, it appears that N-port T-networks have not been previously identified for N > 2, a strange topological asymmetry in circuit theory. We introduce the general N-port T-network and illustrate applicati...
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This paper presents a new modeling approach accounting for the nonlinear description of low-frequency dispersive effects (due to thermal phenomena and traps) affecting electron devices. The theoretical formulation is quite general and includes as particular cases different models proposed in the literature. A large set of experimental results, oriented to microwave GaN power amplifier design, is p...
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Cascode field-effect transistors (FETs) are widely used in the design of monolithic microwave integrated circuits (MMICs), owing to their almost unilateral and broadband behavior. However, since a dedicated model of the cell is rarely provided by foundries, a suboptimal description built by replicating the standard foundry model for both the common source and common gate device is often adopted. T...
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In this paper, we present a novel digital predistorter structure for joint mitigation of frequency-dependent power amplifier (PA) and in-phase and quadrature (I/Q) modulator impairments in direct-conversion radio transmitters. The predistorter is based on an extended parallel Hammerstein structure, yielding a predistorter that is fully linear in the parameters. In the parameter estimation stage, t...
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Using an external tuner-based method, this paper demonstrates a complete millimeter-wave noise characterization and modeling up to 60 GHz for 65-nm MOSFETs for the first time. Due to channel length modulation, the channel noise continues to increase and remains the most important noise source in the millimeter-wave band. Our experimental results further show that, with the downscaling of channel l...
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Conventional radar pulse compressors use either surface acoustic wave devices or fast convolution processing, but both solutions have significant drawbacks. To overcome these drawbacks, an integrated analog pulse compressor for a multiple-input multiple-output (MIMO) radar has been developed with an 0.18-??m CMOS process using an arbitrary waveform generator, analog correlators, and analog-to-digi...
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In this paper, we provide experimental evidence to show that enhanced bit error rate (BER) performance is possible using a retrodirective array operating in a dynamically varying multipath environment. The operation of such a system will be compared to that obtained by a conventional nonretrodirective array. The ability of the array to recover amplitude shift keyed encoded data transmitted from a ...
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This paper presents a novel size reduction technique for designing a Butler matrix using a new type of coupler. This coupler is half the length of a conventional coupler and has a swapped port characteristic wherein the locations of the isolation and coupled ports are switched. These features make the new coupler, called the "swapped port coupler," effective for reducing the size of the Butler mat...
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This paper presents a Ku-band SiGe BiCMOS phased array receive chip capable of forming four-simultaneous beams from two antenna inputs. The design is based on the all-RF architecture with 4-bit active phase shifters and 4-bit variable gain amplifiers in each channel. The four-beam chip results in a gain of 4-6 dB per channel at 13-15 GHz, a noise figure of 10-11 dB, a worst case input P1 dB View full abstract»

Recently, GaN-based low-noise amplifiers (LNAs) were shown to provide high ruggedness together with low noise figure. Since no limiter is required to protect the input, these LNAs allow for simplified receiver architectures. This paper presents an in-depth analysis of the recovery time of a highly rugged LNA. Recovery time is measured in the time domain, and an analytical approximation is develope...
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In this paper, the output power, phase response, and drain efficiency of a class-E power amplifier with shunt capacitance, composed of nonlinear and linear capacitance, is analyzed to manifest the cause of efficiency degradation at low drain dc supply voltage (V dc). Analysis also shows that the drain efficiency at low V dc can be improved by reducing the on-dut...
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The simultaneous noise and impedance matching (SNIM) condition for a common-source amplifier is analyzed. Transistor noise parameters are derived based on the more complete hybrid-?? model, and the dominant factors jeopardizing SNIM are identified. Strategies for narrowband and broadband SNIM (BSNIM) are derived accordingly. A dual reactive feedback circuit along with an LC-ladder matching network...
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A study of amplitude modulation (AM) and phase modulation (PM) noise has been carried out in an SiGe bipolar amplifier, operating in small- and large-signal conditions. Experimental and simulation results show that the evolution of flicker noise and white noise contributions versus carrier power is different in the AM and PM noise spectra. This indicates that specific mechanisms are involved in th...
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This study develops a compact balun layout to minimize amplitude imbalance. Three baluns with different metal layers are fabricated using 0.13-??m CMOS technology and their imbalance performance evaluated. Measurement made using eight metal layers in coil windings at a particular layout reveal that the proposed device exhibits minimal amplitude and phase imbalance of 0.2 dB and ??0.5?? with a chip...
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A CMOS mixer whose linearity is maintained for a wide frequency range is presented. Transconductance (Gm) boosting methods, such as input cross-coupling, current reuse complementary input, and back gate connection, are used to improve overall gain and noise performance. A source-degenerated passive mixer is used to improve noise figure (NF) by increasing the equivalent mixer output impedanc...
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A wide-IF-band transistor mixer has been designed using a 0.13-??m RF-CMOS process where its RF frequency is 8.7-17.4 GHz, local oscillator (LO) fixed at 17.4 GHz, and IF up to 8.7 GHz. Proper layout arrangement for the Marchand balun has been discussed and then implemented; the output amplitude and phase imbalance are less than 0.5 dB and 1 ?? measured in the RF bandwidth. Related theo...
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In this paper, we present the development of low-noise waveguide mixers with NbN/AlN/NbN tunnel junctions at a frequency approaching 1 THz. The mixer was designed to be compatible with MgO substrate. Mixers of the presented design demonstrated much improved receiver sensitivity. This improvement is attributed to the reduction in signal dissipation in waveguide and leakage into an intermediate freq...
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A simple five-port direct receiver achieving broadband performance and high local oscillator to RF isolation is presented. The new circuit comprises three power detectors exhibiting high series impedance, four resistors, and two low-pass and two high-pass phase shifters. It is shown that the phase-shift networks can be designed to optimize receiver operation over a theoretical decade bandwidth. A ...
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A 3-5-GHz ultra-wideband front-end for low-data rate wireless personal area networks is presented in this paper. The circuit, fabricated in a 90-nm CMOS technology, includes a Gaussian-envelope carrier-based transmitter, a direct-conversion down-converter, and an LO frequency synthesizer. A highly accurate Gaussian pulse shape is achieved by using a nonlinear pulse-forming approach, which provides...
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This paper presents a low-complexity and low-cost hardware implementation of a Volterra series-based digital predistorter (DPD). This is achieved by introducing two novel model complexity reduction techniques into the system, namely, lookup table assisted gain indexing and time-division multiplexing for multiplier sharing. Experimental results show that this novel DPD implementation uses much less...
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In this paper, a detailed linearization procedure for dynamic load modulation (DLM) transmitter architectures is proposed for the first time. Compared with the conventional single-input/single-output digital predistortion (DPD) approach used with traditional power amplifiers (PAs), the proposed linearization scheme is based on a regular memory DPD in combination with an efficiency-optimized static...
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A new type of half-mode substrate integrated waveguide (SIW) periodically loaded with different lumped elements and structures is proposed in this paper. The propagation constants, Bloch impedances, and voltage distributions of the Floquet TE-modes are all characterized by solving the eigenvalues of the generalized transmission matrix of a single period. Several typical capacitor-loaded, inductor-...
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A tunable cavity resonator is described that uses a feedback control system to alter its resonant characteristics in response to changes in its environment, without changing the physical dimensions of the resonator. Tuning wires inserted into the cavity are connected or disconnected to the cavity wall under the control of a binary algorithm that searches for desirable operating states from among a...
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Aims & Scope

The IEEE Transactions on Microwave Theory and Techniques focuses on that part of engineering and theory associated with microwave/millimeter-wave components, devices, circuits, and systems involving the generation, modulation, demodulation, control, transmission, and detection of microwave signals. This includes scientific, technical, and industrial, activities. Microwave theory and techniques relates to electromagnetic waves usually in the frequency region between a few MHz and a THz; other spectral regions and wave types are included within the scope of the Society whenever basic microwave theory and techniques can yield useful results. Generally, this occurs in the theory of wave propagation in structures with dimensions comparable to a wavelength, and in the related techniques for analysis and design..